Controlling nanoparticle location via confined assembly in electrospun block copolymer nanofibers.
Coaxial nanofibers with poly(styrene-block-isoprene) (PS-b-PI)/magnetite nanoparticles as core and silica as shell are fabricated using electrospinning.1-4 Thermally stable silica helps to anneal the fibers above the glass transition temperature of PS-b-PI and form ordered nanocomposite morphologies. Monodisperse magnetite nanoparticles (NPs; 4 nm) are synthesized and surface coated with oleic acid to provide marginal selectivity towards an isoprene domain. When 4 wt% nanoparticles are added to symmetric PS-b-PI, transmission electron microscopy (TEM) images of microtomed electrospun fibers reveal that NPs are uniformly dispersed only in the PI domain, and that the confined lamellar assembly in the form of alternate concentric rings of PS and PI is preserved. For 10 wt% NPs, a morphology transition is seen from concentric rings to a co-continuous phase with NPs again uniformly dispersed in the PI domains. No aggregates or loss of PI selectivity is found in spite of interparticle attraction. Magnetic properties are measured using a superconducting quantum interference device (SQUID) magnetometer and all nanocomposite fiber samples exhibit superparamagnetic behavior.
Kalra
Vibha
V
School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA.
Lee
Jinwoo
J
Lee
Jung Hun
JH
Lee
Seung Goo
SG
Marquez
Manuel
M
Wiesner
Ulrich
U
Joo
Yong Lak
YL
D002070:Butadienes / Q000737:chemistry*; D045782:Hemiterpenes / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D019301:Oleic Acid / Q000737:chemistry; D010420:Pentanes / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*
D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; D011137:Polystyrenes; C005059:isoprene; D019301:Oleic Acid